When Do Puppies Stop Growing?

LAST UPDATED 1 MAY 2024

It can seem like the little bundle of cuteness that you brought home turned into a fully grown dog virtually overnight! This is particularly true of miniature and small breed puppies as they have a much faster growth rate than their medium, large and giant breed cousins.

Understanding how puppies grow will equip you with the knowledge to support your puppy's physical and emotional needs to ensure they develop into healthy, happy adult dogs.

We will walk you through the puppy growth timeline and explain why small and medium pups grow at a different rate from large and giant breeds. Find out how puppy's skeletons grow and the influence nutrition and exercise have on the development of bones and muscles. 

Puppy Growth Timeline

There are generally considered to be five main stages of development in a dog's early life:

1. The Neonatal Stage (Birth to 2 weeks) During this stage, puppies are totally reliant on their mother for food and warmth. Their weight usually doubles during this period.
2. The Transitional Stage (2-4 weeks) Puppies' eyes and ears open and they begin to walk. As they begin to explore their environment, puppies' nutritional requirement for muscle and bone growth increases. They need more than mother's milk to continue developing so this is the stage when they start eating solid food. 
3. The Socialisation Stage (4-12 weeks) This is the period in which puppies are weaned from their mother, separated from their litter mates, meet new people and animals and settle into a new home. With so many changes occurring, this is a vital stage for shaping puppies' future behaviour through positive reinforcement training. Careful attention needs to be paid to puppies' nutritional needs to ensure correct bone and muscle growth and healthy development of the digestive tract, nervous system and skin and coat. 
4. The Juvenile Stage (3-6 months) The growth of small breed pups will slow down as they approach their adult weight, so it is important to adjust their food intake to ensure they do not become overweight. Large breeds will continue to grow more steadily and still need approximately double the nutritional requirements of an adult dog of the same breed. Focusing on establishing routines and setting boundaries is of prime importance for juvenile pups. Read through our guides to How to Train a Puppy and Addressing Puppy Behaviour Problems for more information.
5. The Adolescent Stage (6-18 months) While smaller breed puppies have usually finished growing, large puppies will continue to experience skeletal and muscular growth until they reach their adult bodyweight between 18 and 24 months of age.  Just like human teenagers, adolescent puppies will start to test the boundaries and require patience, consistency and engaging activities to help manage their boundless energy.

Understanding Puppy Nutrition

Growing puppies have different nutrient demands in comparison to when they are adult dogs. They need a higher amounts of energy to ensure they achieve an optimal  growth rate while still maintaining a lean body condition. Large and giant breed pups should be fed a diet specifically formulated for large and giant breeds as these will contain less energy than diets formulated for miniature, small and medium breed puppies. 

Energy in puppy diets comes from the calories contained in fats, proteins and  carbohydrates. Fats also provide essential fatty acids which promote skin and coat health, reduce inflammation and encourage healthy development of the eyes and nervous system. Vitamins A, D, E and K are fat soluble and so fat in the diet is required for their absorption and storage. 

Carbohydrates are not an essential nutrient for pups, however, grains, fruit and vegetables provide valuable sources of which spare the use of protein for energy and also fibres which are essential for good digestive health. 

Puppies need the highest amounts of protein in their diets after they are weaned and their protein requirements steadily decrease from this stage. Although protein is required for muscle growth, feeding more than the recommended daily requirement of protein will not make your puppy grow bigger muscles. 

It is common knowledge that puppies need calcium to grow their bones, however an excess of calcium in the diet, particularly in conjunction with low levels of phosphorus, will result in abnormal bone growth. It is very important not to add calcium supplements to complete and balanced puppy and all life stages diets as this will lead to an imbalance in the calcium:phosphorus ratio in the body. Incorrect levels of calcium, phosphorus and also Vitamin D in a puppy's diet can lead to problems like rickets and stress fractures.

Monitoring Your Puppy's Growth

Skeletal Growth and Growth Plates

The size of a dog's skeleton is similar to the frame of a house in that it determines what size the dog will be when it is fully grown. The bones of small puppies stop growing around 6 months of age while the bones of giant breed pups can still be growing up to 24 months of age.  Big bones and joints take a long time to develop and this is why large and giant breeds are often not fully grown until they are two years old.

Bone growth occurs in distinct areas of the bones which are called "growth plates". In long bones like the thigh bone, there is one growth plate at each end which allows the bone to lengthen as a puppy grows. These growth plates are made from cartilage which is soft and flexible and thus prone to injury from trauma or overexercise. Growth plates harden over time due to calcification - this is often called "growth plate closure". Once a growth plate has "closed", the bone can no longer grow. 

Generally, most bone growth takes place between the ages of 4 to 8 months and, after this age, there is very little increase in the length of bones. In most breed, growth plates close around 12 months of age, however, the growth plates of large and giant breeds may stay open for longer.

Assessing Growth Rate

The size of an adult dog is largely determined by the genes it has inherited from its mum and dad and feeding puppies to achieve a controlled growth rate will not affect their final adult body size. Overfeeding puppies and making them grow too quickly can lead to orthopaedic issues like hip dysplasia and arthritis later in life.  

Assessing your puppy's body condition score on a regular basis will help you determine if they are growing at the correct rate. These are the points to look for in a healthy pup:

• Ribs able to be felt without an excess fat covering
• Waist present behind the ribs when viewed from above
• Abdominal "tuck" present behind the ribs when viewed from the side
• Importance of regular veterinary check-ups during the growth phase.

Safe Exercise Practices for Growing Puppies

How do you burn up your puppy's seemingly boundless energy while still protecting their growing bones and joints? Very young pups of any breed and size are fine with multiple short play sessions interspersed with puppy naps. This approach will allow them to exercise their minds and bodies without becoming overtired. This is also a good time to start teaching your puppy to walk on a lead at home.

When your puppy has finished their course of vaccinations and is confident walking on a lead, you can start to venture outside. A good rule of thumb is to walk a puppy for five minutes for every month of their age. For example, you can walk a 6 month old puppy for 30 minutes once or twice daily. 

Large breed puppies have a higher risk of developing joint problems when they are older so low impact exercise such as swimming, walking in water, and walking is a great way to promote muscle and bone growth while safeguarding cartilage and ligaments. Small amounts of jumping and fast running is acceptable, but it shouldn't be your puppy's main form of exercise, and it is best to limit these high-impact activities until your puppy is at least 6 months of age.

Home activities that encourage healthy activity include toys that stimulate them mentally and physically, such as puzzle toys, tug of war, and hide and seek.

For more information, read our article all about How Much Exercise Dogs Need.

Health Check-ups and Vaccinations: Crucial to Puppies' Growth

Vaccination schedules for puppies can vary but generally puppies have a course of 3 vaccinations given 4 weeks apart. The following schedule tends to be the most common:

1. 6-8 weeks: C3 Vaccination 
2. 12 weeks: C5 Vaccination 
3. 16 weeks: C5 Vaccination 

These regular vet visits during a puppy's formative weeks are crucial for monitoring their general health and well being as well as identifying any issues before they become more serious. Your vet will monitor your puppy's growth and development and check for common problems such as dental abnormalities, parasites and orthopaedic problems such as hip dysplasia and elbow dysplasia.

As your puppy continues to grow and transform into an adult dog, regular vet checks and preventative health measures will provide a strong foundation for a long, happy and healthy life. 

Further Reading

What is the best puppy food?

How often should your pet visit the vet?

Desexing your pet - Everything you need to know

How to train a puppy

Best joint supplements for dogs